Pressure Effects on Band Structure of SiC

Van Camp et al [13] also calculated the first and second pressure derivatives by the ab-initio norm-conserving non-local pseudopotential method of the energy differences between the T X-, and L-states of the valence and lowest conduction band and the top of the valence band in ri5 for 3C-SiC. The first-order pressure coefficients for the direct (ri5v-ric) and indirect (T15v - Xu) bandgaps are 61.7 meV GPa 1 and -1.1 meV GPa 1, respectively. The signs of these values are the same for all semiconductors by Paul s rule. However, the magnitudes are quite different from those of other semiconductors. 

TABLE 1 gives the first and second pressure derivatives for 3C-SiC relative to the top valence (Tl5v) band obtained by the calculations [11,13] as well as those obtained by optical measurements [1]. 

TABLE 1 Calculated and experimental values of the band energies (E in eV), first (dE/dP in meV GPa 1) and second (d2E/dP2 in meV GPa 2) pressure derivatives of the energy for 3C-SiC at symmetry points with respect 

---